Apple iOS - definition

Previously iPhone OS, Apple's iOS is the company's own mobile operating system developed and originally released on the Apple iPhone and the Apple iPod Touch back in 2007.

Several years later it was renamed to iOS and was extended to support other Apple devices such as the iPad, 4th Generation Apple TV and the Apple HomePod.

Unlike Google's Android and Microsoft's Windows Phone, Apple does not license iOS to other manufacturers and it is the sole maker and seller of iOS devices.

iPhone OS 1.0 - 1.1.5

The first version of the OS was released initially with the first iPhone (the iPhone 2G as it was pet-named by the public due to the lack of 3G connectivity).

The iPhone OS 1.1.1 brings the following changes (list not exhaustive):

Home button double-click shortcut to phone favorites or music controls.
Mail attachments are viewable in portrait and landscape modes.
Stocks and cities in Stocks and Weather can be reordered.
Support for TV out.

The iPhone OS 1.1.3 brings the following changes (list not exhaustive):

The iPod Touch gets Mail, Maps, Stocks, Weather and Notes apps.
Google Maps on iPhone gets the "Locate Me" button, hybrid map support and the "Drop Pin" feature.
Icons on the home screen can be rearranged and placed on multiple home screens (up to nine).
You can add web shortcuts on the homescreen.
SMS messages to multiple recipients.
Multi-touch keyboard allows pressing of modificator keys such as Shift.

iPhone OS 2.0 - 2.2.1

The iPhone OS 2.0 was introduced with the iPhone 3G. It also marked the introduction of the Apple AppStore and the support for third-party apps by the iPhone OS.

What's new:

A number of email enhancements: push email support, Microsoft Exchange support, mass mail delete, mass mail move, saving attached images enabled.
Search in the contacts list.
Numerous interface localization options: languages/dual language keyboard.
Importing SIM contacts is now possible.
You can view MS Office and iWork attachments in Mail.
Push email, push contacts, push calendar.
Remote device configuration, security policies, remote wipe.
Screenshot capability right out-of-the-box.
Ability to save pics from Safari or Mail to Photos.
Bonjour service discovery protocol.
Addition of Parental controls(apply only to the iPod, Safari, YouTube, iTunes and AppStore).
Scientific calculator in landscape mode.
Image geotagging in the Camera.
A number of Safari web browser changes - photo download, show inline YouTube videos on web pages, new domain extensions available to the .COM button on the keyboard (.net, .edu, .org), entering passwords is more user-friendly showing the last character.
The Apple AppStore is introduced - a ground-breaking application download/install manager.

The iPhone OS 2.2 brings the following changes (list not exhaustive):

Maps app gets Google Street View, public transit and walking directions, you can share location via email.
You can download or stream podcasts via the iTunes application (over Wi-Fi and cellular networks).

iPhone OS 3.0 - 3.1.3

The iPhone OS 3.0 was introduced with the iPhone 3GS. It was available as an update both to the iPhone 2G and 3G models.

What's new:

New Spotlight search tool is now added.
System-wide Cut, Copy and Paste text feature (even from web pages).
Moving apps through homescreens is now easier.
Push background notifications service is introduced.
Stocks app gets news stories and stock details. It also shows graphical history in landscape mode.
Parental Controls are extended to movies, TV shows and App Store content.
Native coice recorder app has been added with editing, cropping and email/MMS sharing. It can record in the background, but doesn't record during calls.
A maximum of 11 application screens now allowed instead of 9 previously
Peer-to-peer via Wi-Fi and Bluetooth now available
Improved predictive dictionary
Turn-by-turn navigation is now possible (but only with third-party apps and third-party maps)
Find My iPhone online service via Apple MobileMe
System-wide landscape keyboard (doesn't work with popups or in Calendar)
There's now MMS support but it's an operator dependent feature. MMS is also not available to iPhone 2G without some tinkering.
Individual search bars in the Messages, Calls Log, iPod music player
New action button in Photos lets you choose multiple pictures to attach to a mail message
You can now send full-res camera photos via email (but only when you copy and paste them in the email body as opposed to attaching them)
SMS forwarding introduced.
Safari gets password and auto fill managers, an anti-phishing tool, proxy servers support, new Copy Link and Open in New Page commands, faster JavaScript performance, video streaming capabilities (HTML 5 video, h.264 and HTTP).
The iPod music app gets shake-to-shuffle function
Third-party apps can now get access to your iPod music library
Media scrubber allows more precise rewinding and fast-forwarding in music and video by 4 variable rates
Support for YouTube accounts (login), commenting and video rating in the native YouTube app
Stereo A2DP Bluetooth streaming is on (not available to iPhone 2G).
Internet tethering is now supported both via Bluetooth and USB (availability depending on the carrier and not to the iPhone 2G).
You can rent and purchase movies straight from the iPhone.
You can manage iTunes/AppStore accounts straight from the device (for instance, toggle between two AppStore accounts)
New way of browsing app screenshots in the AppStore - by scrolling sideways.
Application subscriptions introduced (for a monthly fee).
Third-party applications can offer In-App Purchases.
Optional numeric battery percentage view added
Speaker independent Voice Control. Can be use to call a phone number, play music by song/album/artist name, shuffle music
Built-in support for Nike+ jogging system
TV-out outputs 480p instead 480i resolution
Text-to-speech feature called VoiceOver is included in the new Accessibility menu
System-wide Screen Zoom is also included in the Accessibility menu

iOS 3.2 (iPad only) - 3.2.2

With the introduction of the first iPad the iPhone OS was renamed to iOS. Version 3.2 debuted on the iPad and represents a separate separate branch of the iOS development, which eventually merged back into the main iOS version channel.

Differences compared to the iPhone (list not exhaustive):

The screen auto-rotation works on the homescreen, too.
Compatible third-party apps (not just the system ones) can be broadcasted to an external display via the TV out link
Users can change the homescreen wallpaper (at that time the iPhone only had a customizable wallpaper on the lockscreen)
The Maps app gets a 3D Terrain view mode.
Supports Bluetooth keyboards.
A built-in system dictionary gives definitions of words in supported apps.
Safari has a new thumbnail view of the opened web pages.
The Photos app has a Places tab allowing users to view their photos pinned on the map
Users can now watch 720p HD videos in the YouTube app.

iOS 4.0 - 4.3.5

The iOS 4.0 was introduced with the iPhone 4. The iPhone 2G and the iPod Touch (1st gen) were no longer supported and were left out of this update. The iPhone 3G and the iPod Touch (2nd gen) could be updated, but have feature limitations. The iPhone 3GS and the iPod Touch (3rd generation) could be updated and support all features.

What's new (list not exhaustive):

Homescreen wallpapers
Folder organization of the homescreen icons
Multitasking and fast app switching
Google/Wikipedia search in Spotlight
Bluetooth keyboard pairing support
SMS character counter
SMS search
Email threading
Unified Email inbox
Email archiving is now available when you setup Gmail
Spell checker
iPod music player can now create, edit and delete playlists
5x digital zoom in still camera
Touch-focus in video capture (for video enabled iPhones)
Keyboard layouts span over QWERTY, QWERTZ, and AZERTY
Minor icon design facelifts
FaceTime video call support (only for the latest then iPhone 4, only over Wi-Fi, and only to other FaceTime users)
iBooks e-book and PDF reader

The iOS 4.1 brings the following changes (list not exhaustive):

Fixes iPhone 4 proximity sensor issues.
Fixes Bluetooth connectivity issues.
Fixes iPhone 3G performance issues under iOS 4.x.
Adds High dynamic range camera mode (only to the iPhone 4).

The iOS 4.2 brings the following changes (list not exhaustive):

Introduces AirPlay, which offers wireless Wi-Fi streaming for video, music, and photos (requires an Apple TV).
Introduces AirPrint, which offers wireless printing
Adds text search on web pages in Safari.
Delivers iOS 4 features to the iPad (multitasking, folders, etc.).
The Physical iPad screen rotation lock switch is converted into a sound/silent switch in iOS 4.2 (just like on the iPhones), with a virtual screen rotation lock switch added to the multitasking tray.
The multitasking tray on the iPhone and iPod Touch gets volume controls and AirPlay controls.
Adds the ability to initiate FaceTime calls to the Voice control.

The iOS 4.2.1 brings the following changes (list not exhaustive):

Find My iPhone remote management feature becomes free for updated devices (iPhone 4, iPod Touch (4th gen), & iPad).

The iPhone OS 4.2.5 was introduced only on the CDMA iPhone 4 sold by Verizon. It has an exclusive Personal Hotspot feature, allowing the iPhone to turn into a mobile Wi-Fi hotspot.

The iOS 4.3 was presented along with the iPad 2 and it brings the following changes for the whole family (list not exhaustive):

AirPlay video support for third party apps (requires an Apple TV).
Improved Safari performance with the new "Nitro" JavaScript engine.
Ability to switch on automatic downloads (for iTunes Music and App Store applications).
Ability to cancel and delete an app, which is still downloading.
Stream from an iTunes library to iOS using Home Sharing.
Personal Hotspot feature (Wi-Fi hotspot for up to 5 simultaneous devices) on supported carriers. (GSM iPhone 4 only)
Ability to choose function of iPad's physical switch between rotation lock or mute.
Photo Booth & FaceTime app (iPad 2 only).

iOS 5.0 - 5.1.1

The iOS 5.0 was introduced with the iPhone 4S.

What's new:

Revamped notifications - real time on-screen notifications, lockscreen notifications and pull-down Notification Center.
iMessage service in the Messaging app enabling instant messages to other iOS users.
Reminders - including location-aware options.
Customizable notification sounds - email, voicemail and calendar alerts.
Twitter integration.
iCloud service integration – wireless backup and restore, app and content syncing.
Enhanced Camera app - viewfinder grid, can use a volume button as a shutter key.
Integrated photo editing - crop, auto enhance, rotate and red-eye fix.
Updated Safari browser - tabbed browsing (on iPad), private browsing mode, integrated Reader, Reading list and optimized performance.
Dictionary lookup throughout the interface.
Computer free operation - independent activation, OTA updates, iCloud backup and restore.
Wi-Fi synchronization with iTunes with automatic operation.
New features in the Mail app - Bold, Italic, Underline and Quote options, extended Search, mass Mark as Read/Unread and Flag setting, Add/Delete mailbox folders.
Updated Calendar (new weekly view) and Game Center apps.
Newsstand app combining all of your magazine subscriptions.
Music player now called Music instead of iPod, has a new icon.
Separate Video player app on the iPhone.
AppStore purchase history.
New Storage management options (list of and info about all installed apps).
AirPlay screen mirroring for the iPad and iPhone 4S (requires an Apple TV).
New accessibility options involving the LED flash, custom vibrations and Assistive Touch.
Maps app gets the option to print maps, to find alternate routes and there is also traffic information in supported regions.
Introduces a built-in basic photo editing: crop, red-eye, auto-enhance and rotate photos.
Ability to create keyboard shortcuts to replace custom phrases. By default includes “omw” which expands to “On my way!”.
Spotlight search now includes Reminders and searches through Messages.
Adds a new weather forecast tab for the user's current location.
Week view in landscape orientation of the Calendar.
Siri voice control (iPhone 4S only and available only in English, French and German). Retains beta status throughout the lifetime of iOS 5.x. Allows speaker independent commands in natural language, voice dictation and Text-to-Speech functionality.
iPad only - Allows a split keyboard: swipe up or pull apart to split keyboard in half.
iPad only - Adds an undock keyboard option: keyboard can now be moved up and down the screen.
iPad only - Introduces tabbed browsing.
iPad 2 only - Adds multitasking gestures with 4 or 5 fingers.

The iOS 5.0.1 brings the following changes (list not exhaustive):

Adds multitasking gestures with 4 or 5 fingers to the original iPad.
Adds a new camera button to the lockscreen - visible only after a double click of the Home button.

The iOS 5.1 was introduced along with the iPad 3 and it brings the following changes (list not exhaustive):

Redesigned Camera app (for iPad).
Camera shortcut on lock screen is now always visible and activates the camera with a slide-up gesture.
Improved face detection and video stabilization (iPhone 4S & iPad 3 only).
Siri receives improved dictation skills and Japanese language support.

iOS 6.0 - 6.1.6

iOS 6.x is the current generation of iOS. It was introduced with the iPhone 5, but is also the out-of-the-box OS for the iPod Touch (5th gen), iPad 4 and the iPad Mini.

What's new:

Siri becomes available on iPad 3 and the iPod Touch (5th gen.)
Siri now speaks Canadian English, Spanish (Spain/Mexico), Italian, Italian (Switzerland), Korean, Mandarin (Chinese/Taiwan), Cantonese (Hong Kong.)
Siri can now provide sports scores, movie and restaurants reviews. It can launch apps and do status updates on Facebook or Twitter.
System-wide Facebook integration: Facebook contacts and events appear in the phonebook and calendar.
Notification center gets quick Facebook/Twitter update keys
New Maps app with TomTom data, turn-by-turn voice navigation, 3D/Flyover view mode, Lock screen integration and annonymous traffic info crowdsourcing.
Improved Safari browser with iCloud tabs, full-screen mode, offline reading, faster performance, support for up to 25 open tabs on iPad, photo upload to web forms.
Passbook e-ticket app handles loyalty coupons, boarding passes, tickets.
The Photo app can share photos with other iOS users via Photo Streams. Likes and comments are supported.
Updated Mail with VIP and Flagged mailboxes.
Unified FaceTime/iMessages ID. FaceTime now works over the cellular network.
New UI for the App Store, iTunes Store, iBooks Store, Music, Weather apps.
Downloading of new apps continues in the background and no longer returns the user to the home screen.
Newly downloaded apps get a blue "New" ribbon.
Updating an app no longer requires a password.
You can set songs from your music library as alarm tones.
Improved privacy settings.
New accessibility options and guided access (single-app mode for kids.)
Improved HDR camera function.
Built-in Panorama mode in the camera.
Game Center now supports challenges (achievements).
Reject call with SMS.
Do Not Disturb mode allowing users to avoid calls and notifications in certain times of the day.
Lost mode.
Improved keyboards and auto-correction.
The manual display brightness override only works temporarily.
Users can create custom vibrations for various alerts.
French, German, and Spanish dictionaries.